/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.db.mpp.plan.expression.leaf;

import org.apache.commons.lang3.Validate;
import org.apache.iotdb.db.mpp.plan.expression.ExpressionType;
import org.apache.iotdb.db.mpp.plan.expression.visitor.ExpressionVisitor;
import org.apache.iotdb.db.mpp.plan.planner.plan.parameter.InputLocation;
import org.apache.iotdb.db.mpp.transformation.dag.memory.LayerMemoryAssigner;
import org.apache.iotdb.tsfile.file.metadata.enums.TSDataType;
import org.apache.iotdb.tsfile.utils.ReadWriteIOUtils;

import java.io.DataOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.List;
import java.util.Map;

/**
 * Constant operand
 */
public class ConstantOperand extends LeafOperand {

    private final String valueString;
    private final TSDataType dataType;

    public ConstantOperand(TSDataType dataType, String valueString) {
        this.dataType = Validate.notNull(dataType);
        this.valueString = Validate.notNull(valueString);
    }

    public ConstantOperand(ByteBuffer byteBuffer) {
        dataType = TSDataType.deserializeFrom(byteBuffer);
        valueString = ReadWriteIOUtils.readString(byteBuffer);
    }

    @Override
    public <R, C> R accept(ExpressionVisitor<R, C> visitor, C context) {
        return visitor.visitConstantOperand(this, context);
    }

    public TSDataType getDataType() {
        return dataType;
    }

    public String getValueString() {
        return valueString;
    }

    public boolean isNegativeNumber() {
        return !dataType.equals(TSDataType.TEXT)
                && !dataType.equals(TSDataType.BOOLEAN)
                && Double.parseDouble(valueString) < 0;
    }

    @Override
    public boolean isConstantOperandInternal() {
        return true;
    }

    @Override
    public void bindInputLayerColumnIndexWithExpression(
            Map<String, List<InputLocation>> inputLocations) {
        // Do nothing
    }

    @Override
    public void updateStatisticsForMemoryAssigner(LayerMemoryAssigner memoryAssigner) {
        // Do nothing
    }

    @Override
    public String getExpressionStringInternal() {
        // Currently, we use Expression String to distinguish the expressions.
        // So we need to distinguish number 1 and text "1"
        return dataType.equals(TSDataType.TEXT) ? String.format("\"%s\"", valueString) : valueString;
    }

    @Override
    public ExpressionType getExpressionType() {
        return ExpressionType.CONSTANT;
    }

    @Override
    protected void serialize(ByteBuffer byteBuffer) {
        dataType.serializeTo(byteBuffer);
        ReadWriteIOUtils.write(valueString, byteBuffer);
    }

    @Override
    protected void serialize(DataOutputStream stream) throws IOException {
        dataType.serializeTo(stream);
        ReadWriteIOUtils.write(valueString, stream);
    }
}
